Objective：This study compared oncologic outcomes between thoracoscopic lobectomy and segmentectomy,as well as detected the relevant independent risk factors in patients with p-stage IA(T1aN0M0) pulmonary adenocarcinoma. Methods：The clinical, pathological, and survival data of 159 cases in stage IA pulmonary adenocarcinoma who underwent pulmonary resection in the First Affiliated Hospital of NJMU from December 2012 to January 2014 were retrospectively analyzed．Kaplan-Meier method was used for analysis of survival，and the Cox Regression analysis was used to examine independent predictors for prognosis. Results: The 3-year overall survival rates and progression-free survival rates for the patients who underwent lobectomy were 88% and 85%，respectively, compared with 97% and 96% for the patients who underwent lobectomy(P＜0.05). Cox Regression analysis showed that tumor size and pathological subtype were the independent prognostic factors on recurrence(RR=18.219，95％CI：2.484～133.652，P=0．004；RR=2.107，95％CI：1.403～3.163，P<0.001) and death(RR=12.765，95％CI：1.332～122.37，P=0．027；RR=2.223，95％CI：1.376～3.499，P=0．001). Three-year overall survival rates and progression-free survival rates were 98% and 97%, 88% and 88%, 78% and 78%, and 75% and 58%(P<0.05) for lepidic, acinar, papillary, micropapillary and solid predominant pulmonary adenocarcinoma tumors, respectively. Conclusion：Tumor size and pathological subtype have significant influence on the prognosis of patients in stage IA pulmonary adenocarcinoma. For the patients in stage IA pulmonary adenocarcinoma, the prognosis of thoracoscopy segmentectomy is not second to that of lobectomy on the premise of strictly mastering the surgical indication.